Members of the Legislature’s Criminal Justice Committee are wisely, if belatedly, meeting this summer to consider how more than a dozen bills that call for longer sentences would affect the state’s already overcrowded prisons. If lawmakers are serious about the consequences of mandatory sentences and other measure that increase jail time, they should require that every such bill show how it would increase the prison population and corrections costs. Better yet, these should be offset by changes elsewhere in the prison system.

A pay-as-you-go, or pay-go, budget requires reducing programs or raising revenues in other areas to offset new programs or tax cuts. A prison pay-go would require that bills calling for longer or mandatory sentences require disclosure of the costs of such requirements. For example, would new jail space need to be built? Would inmates in prison have to been sent elsewhere to make room for the new convicts? Such disclosure would make it clear to legislators and the public that being “tough on crime,” whether it be drunken driving or sexual molestation, comes at a cost.

Mandatory sentencing enacted by the Legislature is the biggest reason for the overcrowding, Corrections Commissioner Martin Magnusson has told lawmakers. A recent report by the Corrections Alternatives Advisory Committee notes that the large increase in the number of inmates is the result of more people being sentenced to jail and staying longer, not because of an increase in crime. In the past 20 years, the average daily population at state prisons had risen 71 percent.

During the 122nd Legislature, lawmakers passed laws to toughen the sentences for habitual drunken drivers and for sex offenders whose victims were under the age of 12. They also passed several laws that expanded the definitions of crimes that could require jail sentences. Each means that more people will be crammed into the state’s prisons.

This year, lawmakers considered many bills to toughen sex crime penalties. One would have required a 25-year minimum sentence for those convicted of sexual crimes against victims under 12 and life sentences for a second offense. This could cost up to nearly $1 million per convict, according to the bill’s fiscal note.

Tougher or mandatory-minimum sentences may be needed, but lawmakers should be required to know and account for their fiscal consequences, by either finding the money needed to cover the added costs or by designating other classes of prisoners for early release to make room for new ones.